Electric welding apparatus



E. J. F'ODANY ELECTRIC WELDING APPARATUS April 26, 1938.

Filed March 18, 1935 2 Sheets-Sheet 1 Y INVENTOR. Fan draw Paid/7 37,

BY Wfifi fl ATTORNEYS.

April 26, 1938. E. J. .PODANY ELECTRIC WELDING APPARATUS 2 Sheets-She'et 2 x3 4/ Om INVENTUR. fin 41: I 722421 7 BY M124 ATTORNEYS.

, Patented Apr.26,1938

UNITED STATES Emc'rarc WELDING APPARATUS 4 Edward J. Podany, Detroit, Mich" assignor to The Murray Corporation of America, a corpora-- tion of Delaware Application March 18, 1935, Serial No. 11,537-

'1 Claims.

The present invention relates to welding tools and particularly to such tools as are usually referred to as of the pry bar type.

In many lines of manufacture in which electric welding is employed in the factory assembly of parts, and of which the automobile industry is an example, the parts to-be welded are clamped together upon a jig, which forms one terminal of the welding circuit. A member stationarily mounted with respect to the jig forms the other terminal of the welding circuit. A tool commonly referred to as a welding gun, is provided with a welding electrode for engaging the work material at the point to be welded, and is used to complete the circuit between the work material and the above mentioned stationary second terminal.

Frequently, the welding gun is provide'd with a Dimculty has been experienced in the use of welding guns of this character for the reason 0 that the operator is reliedtupon to engage the work with the proper pressure, and to accomplish this before the flow of welding current is initiated. Through carelessness'or fatigue, the weldingpressures thus obtained vary considerably among the several welds, thus introducing irregular welding action. Frequently also, the flow of welding current is initiated too soon, causing burning of the work as well as of the electrodes.

0 In accordance with the.present invention,

means are incorporated into the welding gun to insure consistent contact pressures for each welding operation and to insure that'this proper contact pressure is attained before the welding action is ,5 begun. In the illustrated embodiments, this mechanism responds to a press button formed integrally with the welding gun. In the operation of a welding gun organized in accordance with the present invention, the welding gun is placed upon the work to be welded and against the previously mentioned prying member, which may also constitute the second terminal of the welding circuit. Upon operation of the press button, the gun is ilrst pried into engagement with the piece to be welded with a predetermined force, and thereafter the welding circuit is completed. a

Any desired meansmay be employed to interrupt the flow of welding current upon completion of the weld. Preferably, however, an arrange- 5 ment such as disclosed in the co-pending application of Orin J. Ryder, Serial No. 742,921, filed September 6, 1934, and assigned to the same assignee as the present invention, is employed. As described therein, the welding circuit is controlled by means of a relay, which may respond to the above mentioned press button, and which, upon operation, completes the welding circuit and maintains it complete for a predetermined length ofi'time. Upon interruption of the welding circult by this relay, recompletion thereof is prevented unless the relay solenoid is tie-energized and then again energized.

The principal object of the present invention, accordingly,- is to provide a welding gun of the pry bar type which embodies automatic means to insure a proper contact pressure and to insure that the-flow of welding current is not initiated until after such proper contact pressure has been obtained. It is also an object of the present invention to provide a welding gun having the above characteristics, which is simple in' con struction, positive in operation, and which may be economically manufactured. Other objects and advantages of the .present invmtion appear s in the following description and in the following claims.

In the drawings:

Figure 1 is a view in side elevation, partly in section, of a pry bar welding gun embodying the present invention,

Fig.2 is a view taken on the line 2-2 of Fig. 1,

Fig. 3 is a view in side elevation, partly in section, of a modified form of gun embodying the present invention, 40

- Fig. 4 is a view taken on the line 4-4 of Fig. 3,

Fig. 5 is a view in side elevation, partly in section, of a second modification of the present irivention, and

Fig. 6 is a view taken on the line 6-6 of Fig; 5.

Referring to Figs. 1'. and 2, the welding gun comprises, generally, a housing- I formed in the shape of a handle grip, to which an electrode 'portion 2 is removably mounted by bolts 3. Member 2 is formed to partially surround a prying member 4 which, as previously mentioned, preferably constitutes one terminal of the' weld- 4 ing supply circuit, and terminates in an electrode 5, illustrated as hearing against two pieces 6 and l which represent the work to be welded. Pieces u 6 and 1 may be mounted on a jig 8 which, as previously mentioned, forms the other terminal of the welding supply circuit. It will be understood .that in general practice, pry 4 and jig 8 extend at right angles to the plane 01' the paper and that the pieces to be welded, such as pieces 6 and 1, are attached to jig 8 at various points along its length by suitable clamps (not shown). With this arrangement, the welding gun may be advanced from one welding position to another along members 4 and 8.

Housing I ishollowed out to form a piston cylinder 9, which. receives a piston It. A plunger l3, disposed to bear against a member 14 to produce the proper welding pressure, passes through piston Ill, packing gland II and packing cup l2 and is secured thereto by nut l5. It will be understood that support l4 extends along pry 4 and jig 8 and may be formed integrally with either of these members.

Chamber 9 communicates with a source of air pressure l6 through intake ports l1 and I8. Port l8 and a suitable exhaust port I9 are controlled by a valve 28 formed at the end of press button 2|. Press button 2| fits into a circular recess formed in the'end of housing I and normally occupies the dotted line position under the influence of spring 23 which forces shoulder 24 against stop 25. Stop 25 may be threaded into housing Switch 26, secured in a recess 21 by means of set screw 28, may be of usual construction and pref erably comprises suitable contact structure which responds to a plunger 29. The arrangement is preferably such that the contacts are closed when plunger 29 occupies the illustrated extreme position and are open upon inward movement of plunger'29. Switch 26 may also comprise a spring (not shown) to bias plunger 29 to the illustrated position.

In operation, the welding gun is placed in the illustrated position, and button 2| is moved to the full line position, in which valve 28 closes exhaust port l9 and connects intake port |8 to the source of supply l6. The consequent flow of air into cylinder 9 forces piston ID to the illustrated position against the force of spring 30, which bears against a seat 3| threaded into housing The movement of piston l8 forces plunger l3 into engagement with stop l4, which action tends to rotate the gun around member 4 and forces electrode 5 firmly into engagement with the pieces to be welded.

As piston l0 reaches the end of its movement, plunger 29 reaches contact closing position, interconnecting conductors 32. It will be understood that conductors 32 control the operating circuit of switch mechanism (not shown) which, upon actuation, connects jig 8 and member 4 to the source of welding current. As mentioned, the

switch mechanism preferably embodies the ar- 1 rangement shown in the previously mentioned Ryder application, so that after the expiration of a predetermined interval, the welding circuit is interrupted. Alternatively, of course, independent manually operated means may be employed to interrupt the welding circuit.

Upon completionof the welding operation and interruption of the welding circuit, button 2| may be released and allowed to resume the dotted line position, as influenced by spring 23, This action moves valve 20 to the left in Fig. 1, closing port H and connecting port l8 to exhaust port l9. Accordingly, plunger I3 moves somewhat away from surface l4 under the influence of spring 30. In the course of this movement,

plunger 28 is actuated to disconnect the conductors 32 from each other.

The modification illustrated in Figs. 3 and 4 comprises an arrangement in which a plunger for obtaining proper contact pressure, and a switch for initiating the flow of welding current, are controlled independently and in proper sequence by means of a manually controlled member associated with the gun and which, as illustrated, takes the form of a trigger. In accordance with this modification also, upon release of the trigger, the welding supply circuit is first interrupted and thereafter the contact pressure is relieved.

Referring to Figs. 3 and 4, welding gun 46 comprises a shank 4| which terminates in an electrode '42 and includes a portion 43 formed to partially surround a prying member 44. Electrode 42 bears against the work pieces 45 and 46 which, in turn, are associated with jig 41. Jig 41 and member 44 constitute the two terminals of a welding circuit, described in connection with Fig. 1.

Housing section 48 formed to provide a convenient hand grip, is hollowed out to provide a cylindrical piston chamber 49, which receives a piston assembly. The piston assembly comprises a. cored out casting 50 of cylindrical cross section having outer shoulders 5|, 52 and 53 formed thereon, a sleeve 54 provided with an annular shoulder 55, a piston head 56, packing gland 51 and cooperating packing cup 58, and an assembly bolt 59 which terminates in an enlarged plunger section 60 disposed to cooperate with a support 6 A sleeve 62 forms a journal for the enlarged p0rtion of member 58 and is provided with an annular shoulder 64, which cooperates with shoulder 6| to limit the motion of the piston assembly in one direction and with shoulder 55 to limit the motion of the piston assembly in the other direction. A

biasing spring 65 tends to force the piston assembly .into the chamber 49.

The above described parts may be assembled as follows: Sleeve 62 is slid upon member'58 to the position indicated; after which sleeve 54, spring 65, piston head 56, packing gland 51 and packing cup 58 may be applied and the assembly completed by nut 66 and-lock washer 61. The completed assembly may then be inserted in chamber 49 and sleeve 62 secured in place therein by means of a set screw 63.

Chamber 49 communicates with a source of air pressure 16 through ports 1|, 12' and 13 and valve 14, or with an exhaust port 15 through the same ports and ball valve 16. Valves 14 and 16 are both controlled by a plunger 11 journaled at 18. Plunger 11 is biased to the illustrated position by the pressure exerted on the end of valve 14,

' and is actuable by trigger 19, rotatably mounted on pin 80.

Conductors 8| and 82 enter a cylinder switch 83 having a contact controlling plunger 84, and is preferably of the type described in connection with Fig. 1.

Upon rotation of trigger 18 in a clockwise direction, plunger 11 forces ball valve 16 to the right, closingexhaust port 15, and forces valve 14 to the right, connecting chamber 49 to source 18. This action forces plunger 66 into engagement with support 6| with a force determined by the pressure in line 18. Upon continued movement of trigger 19, plunger 84 actuates switch 83 to circuit closing position, connecting conductors 8| and 82 together. As described in connection with Fig. 1, this action connects jig 41 and pry 44 to a source of welding current. In the 7 absence of timing mechanism such, for example, as is described in the previously mentioned Ryder application, the welding action continues as long as trigger I is maintained in the actuated position.

Upon release of trigger I0, plunger 84 first reopens the circuit between conductors 0| and 02. As the movement of trigger I0 continues, valve I4 resumes the illustrated position, discone necting chamber, 49 from supply line I0, and valve ll connects chamber 49 to exhaust port I5. This of welding current is prevented until the contact pressure reaches a predetermined value.

In Figs. and 6, gun 00 includes two pivotally related sections 9i and 02. Section 0| is provided with an electrode 93 which engages work pieces placement which occurs between'thue membersi4 and SI, and a curved portion 00 which partially surrounds pry 01. One end of section 02 is formed as an operator's handle, and the other end is formed as a bifurcated yoke in which section ll is pivotally mounted by means of pin 00. A biasing spring 90 is mounted in cylindrical recesses I00 and IM formed in sections 0| and 02, respectively, and tends to maintain the parts inthe illustrated relative positions. A switch comprising housing I02 and piston I0! is provided with suitable contact structure (not shown) to control the welding current supply circuit. Housing I0! is fitted into a recess I formed in member 02 and is secured therein by means of a set screw I05. is provided with a shoulder portion I06, secured thereon by means of a set screw I0'I, which bears against a cooperating shoulder I00 formed in portion I. Plunger Illfits somewhat loosely into housing I02 to accommodate the angular disin the operation of the gun and is arranged to close the circuit between two conductors (not shown), carried in cable H0, in the manner described in connection with Fig. 1.

If desired, electrode 03 may be provided'with a water cooling system of the type shown in Fig. 3, a flexible conduit. III being illustrated as a convenient means for conducting the water supply between the relatively movable members 0i and 0!.

To eifect a welding operation, handle 82 is swung in a counter-clockwise direction about pivot 00. This action compresses spring 99, forcing electrode 03 into contact with work pieces 04 and 05 with a force determined by the spring characteristics, and also moves plunger I03 further into housing I02.

Upon movement of plunger I03 into housing I02 to a predetermined degree, the contact which interco'nnects the supply circuit conductors is completed, and causes switching mechanism (not shown) to connect Jig II! and pry'fl to a source of welding current in the manner described in connection with Fig. 1. This action occurs only after compression of spring 90 to a predetermined degree corresponding to the desired welding contact pressure.

If the welding current supply circuit is entirely Piston I03 under the control of the circuit controlled by switch I02, it will be understood that the welding action will continue as long as arm 021s held in the just described rotated position, and will be stopped if arm 92 is released to the illustrated position, or is released far enough to reduce the welding contact pressure below the predetermined value. Preferably, however, the welding current supply circuit embodies timingmechanism of the type illustrated in the above mentioned Ryder application, so that the welding current supply is automatically out 01f at the end of a predetermined welding interval. In this event, release of arm 92 serves merely the purpose of permitting welding gun 90 to be moved to the next welding point.

Although specific embodiments of the present invention have been herein illustrated and described, it is evident that various modifications maybe made in the construction and arrangement of parts without departing from the spirit and scope of the present invention. It is to be understood, 'accordingly,.that the described embodiments are to be considered in an illustrative, and not in a limiting, sense.

What is claimed is:

1. In an electric welding gun of the pry bar type, in which a support is provided to pry an electrode formed on the gun into engagement with the work to be welded, the combination ofa member embodied in said gun for cooperation with said support; a second member embodied in said gun and disposed between said electrode and said first member for cooperation with an additional support to form a fulcrum for said gun; and means for moving said first member relative to said gun to rotate said gun about said fulcrum to establish a predetermined welding pressure.

-2. In an electric welding gun of the pry bar type, in which a support is provided to pry the electrode formed on the gun into engagement with the work to be welded, the combination of a member embodied in said gun for cooperation with said support; a second member embodied in said gun and disposed between said electrode and said first member for cooperation with an additional support'to form a fulcrum for said gun; contact' mechanism embodied in said said gun for controlling the welding current supply; and means for 'moving said first member to rotate said, gun about said fulcrum and for actuating said contact mechanism.

3. In an electric welding gun of the pry bar type, in which a first support is provided to pry an electrode formed on the gun into engagement with the work to be welded, the combination of a member embodied in said gun for cooperation with said support; a second member embodied in said gun for cooperation with a second support to form a support for said gun; and means for moving said first member relative to said gun to force said gun into engagement with said work and said first and second supports and establish a predetermined welding pressure between said electrode and said work.

4. In an electric welding gun of the pry bar type, in which a first support is provided to pry an electrode formed on the gun into engagement to the axis of said body into engagement with in said body for cooperation with a second support to form a support for said gun; and means for actuating said plunger to force said gun into engagement with said work and first and second supports and establish a predeterminedwelding pressure between said electrode and said work.

5. In an electric welding gun of the pry bar type, in which a support is provided to pry an electrode formed on the gun into engagement with the work to be welded, the combination of a longitudinally extending gun body; a hand grip portion formed adjacent one end of said body; means adjacent the other end of said body to support said electrode; a plunger embodied in said gun adjacent said hand grip portion and movable transversely thereof for cooperation with said support; a hook-like member positioned intermediate said electrode and said plunger adapted to have fulcruming relation with an additional support for said gun; and means for actuating said plunger to cause said gun to rotate about said additional support and establish a predetermined welding pressure.

6. In an electric welding gun of the pry bar type, in which a support is provided to pry an electrode formed on the gun into engagement with the work to be welded, the combination. of a hand grip portion and an electrode arm projecting from said hand grip portion, said elec- 2,115,084 said first support; a second member embodied trode portion being adapted to support said electrode adjacent the remote end thereof; a plunger embodied in said hand grip portion and adapted for cooperation with said support; a hook-like member embodied in said electrode portion and adapted to cooperate with a supply busbar to supply said electrode and to form a fulcrum for said gun; and means for actuating said plunger.

to cause said gun to rotate about said busbar and establish a predetermined welding pressure;

7. In an electric welding gun of the pry bar type, in which a support is provided to pry an electrode formed on the gun into engagement with the work to be welded, the combination oi! a hand grip portion; an electrode arm extending in one direction from said hand grip portion and adapted to support said electrode adjacent the remote end thereof; an actuating portion extending in another direction from said hand grip portion; a plunger embodied in said hand grip portion and adapted to-cooperate with said support; a hook-like member embodied in said electrode portion and adapted to cooperate with a supply busbar to supply said electrode and to act as a fulcrum for said gun; and a control means embodied in said actuating portion of said gun 

